A spacewalk by Russian cosmonauts outside the International Space Station was cut short on Wednesday because of a suit glitch.
Cosmonauts Oleg Artemyev and Denis Matveev were working on the European Robot Arm and the Nauka module when commander Artemyev’s suit experienced a battery problem.
Both made it safely back into the space station when the seven-hour spacewalk cut short after just two hours.
“Expedition 67 Commander Oleg Artemyev and Flight Engineer Denis Matveev, both of Roscosmos, were instructed by Russian flight controllers to end the Aug. 17 spacewalk at the International Space Station due to a battery power issue on Artemyev’s Orlan spacesuit,” Nasa said.
They had completed the installation of two cameras on the European robotic arm.
But then commander Artemyev’s spacesuit started showing abnormal battery readings.
Mission control in Moscow instructed the cosmonauts to return to the Poisk airlock to connect to the space station’s power supply.
“Cosmonaut Sergey Korsakov, inside the station, is placing the European robotic arm in a safe configuration, and Matveev has just returned to the Poisk airlock. The duo was never in any danger during the operations,” Nasa said.
Russian flight controllers could be heard during a live-stream of the spacewalk, instructing the cosmonauts to “drop everything and go back right away”.
Astronauts routinely carry out spacewalks to do maintenance tasks on the exterior of the floating laboratory.
This was commander Artemyev’s seventh spacewalk and Mr Matveev’s third.
Russian cosmonauts wear Orlan suits. These spacesuits allow astronauts to breathe in the vacuum of space while protecting them from a harsh environment of temperature extremes and the risk of radiation damage.
Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Centre for Astrophysics, said on Twitter that the incident on Wednesday was not a safe situation.
“Nasa PAO [public affairs officer] doing the usual trying to minimise things: ‘Artemyev is in no danger whatsoever'. Of course that is never true during a spacewalk,” he said.
“And in particular, if you are working outside in vacuum in a malfunctioning spacesuit, anyone who says you're in no danger — to quote John Young — 'don't understand the problem'.
“To be clear, I don't expect there to be any problem getting him inside, but that doesn't mean it's a safe situation.”
Spacewalks usually finish without a hitch, but there have been other instances where astronauts were in danger.
In 2013, water leaked into the helmet of Italian astronaut Luca Parmitano during a spacewalk.
His eyes, nose and ears and part of his mouth were filled with water, but he managed to return to the airlock in time.
Once he was safely inside, he and his colleagues discovered that 1.5 litres of water had filled the helmet.
The spacewalk, which was meant to be 6.5 hours long, was cut short after only about 45 minutes.
Last June, a spacewalk by French astronaut Thomas Pesquet and Nasa astronaut Shane Kimbrough was cut short because there were issues with their spacesuits.
About three hours into the spacewalk, Mr Kimbrough lost data on his spacesuit’s display unit, and then there was a sharp increase in the pressure reading on his spacesuit.
They were supposed to install a new set of solar arrays on the station but the trip was cut short after a nearly seven-hour spacewalk.